A tumor, such as a polyp and an early cancer, formed in a mucosa of a digestive tract, such as a stomach and a large intestine, can be now resected by an endoscopic surgery using endoscopic mucosal resection (EMR) and ESD without abdominal section. In particular, a flat tumor and a large tumor having a size of several centimeter are difficult to process by EMR, and can now be efficiently resected by employing ESD. Ordinary ESD is performed in the following procedures.
(1) The circumference of the lesion is marked.
(2) A local injection drug, such as physiological saline or a hyaluronic acid aqueous solution, is injected the submucosal layer for prominence.
(3) The circumference of the lesion is cut with a knife.
(4) The submucosal layer is dissected.
(5) The tumor is recovered.
In the procedure (4), however, the mucosa to be resected may cover the field of view, and the dissected mucosa may be readhered, in some cases, which may cause prolongation of the procedure time. Furthermore, the field of view may not be sufficiently maintained, which concerns about bleeding due to damage of a blood vessel and perforation of a muscular wall.
For solving the problems, various mucosal resection and dissection assisting tools for removing the resected mucosa from the processed area, such as medical grasping equipments and medical traction equipments, have been proposed (see Patent Documents 1 to 5).
However, the traction with a magnetic anchor involves such problems that a large-size equipment is required for traction, movement of the magnetic anchor inside the digestive tract may damage the mucosa (Patent Document 1).
In the method, in which a clip is attached to the other mucosal portion than a lesion, to which a clip and a spring traction device attached to the mucosa of the lesion are connected, thereby resecting the submucosal layer of the mucosa of the lesion, it is necessary to attach the clip to the normal mucosa portion, which damages the unlesioned portion. Furthermore, the lesion and the mucosa on the opposite side are attracted to each other, which concerns about narrowing the operative field (see Patent Documents 2 to 4).
In the case where a mucosal resection and dissection assisting tool that is introduced beside the endoscope, it is necessary to introduce plural tubes into the narrow digestive tract, which may concern about an operational error of the endoscope. Furthermore, there is a concern that the assisting tool may be erroneously moved during operation of the endoscope, which may bring about troubles in the traction operation. Moreover, the assisting tool can be moved only in the same direction as the endoscope, which restrict the direction of opening the mucosa, and it cannot be moved during the endoscopic operation in a direction that is different from the moving axis of the endoscope (see Patent Document 5).